The present invention relates to a conveyor for transporting articles such as letters, mail parcels, CDs, and other types of articles, in particular articles of a relatively light weight such as, e.g., of a maximum weight of about 8 kg, in particular a maximum weight of about 5 kg (although it will be understood that the principles of the invention can be utilized also in connection with articles of a higher weight than about 8 kg). In particular, the invention relates to a conveyor which allows a high degree of adaptability to requirements or constraints with respect to the space it can occupy and the path along which the conveyor units can travel.
Conveyors for letters, mail parcels, CDs, videotapes, books and other relatively light articles should be designed so that they can relatively easily be installed and operated under widely varying space conditions, both with regard to the amount of space the conveyors can occupy and with respect to the three-dimensional configuration of the space available. Examples of conveyors in which the conveyor units are capable of travelling along a curving path extending between different vertical positions appear from AT Patent No. 347.333 and Swedish published patent application No. 92,026,749-9.
The present invention relates to such conveyors that are highly flexible with respect to their installation and operation and which permit the conveyor units thereof to follow paths in any desired direction; which can be installed and operated in a space comprising more than one floor and/or on walls; in which a loading station can be installed directly above or directly under a discharge station, and/or loading stations or discharge stations can be installed directly above each other; and which can be made economically and yet deliver a highly efficient and flawless operation.
The conveyor according to the invention comprises
a plurality of conveyor units,
an endless carrier means, such as a chain, to which each conveyor unit is connected,
an endless main track in which the carrier means is moving in a transport direction, said track comprising at least a first substantially straight main track section, a second substantially straight main track section, and a curving main track section being connected at a first end to the first main track section and at a second end to the second main track section, the first and second main track sections being arranged in two planes in a vertical level so that their respective transport directions are of opposite direction,
each conveyor unit being connected pivotally to the carrier means so as to allow the conveyor unit to pivot relatively to the chain about a main axis of the conveyor unit, each conveyor unit comprising an article-supporting member that extends away from the vertical plane of the carrier means, a first guide member of the conveyor unit, and
first guiding means arranged in a vertical plane being parallel to the vertical plane of the carrier means and adapted to co-operate with the first guide member of each of said plurality of conveyor units when the conveyor unit moves along at least a part of the at least one curving section of said main track, so as to counteract or prevent the article supporting member from tilting from its position relative to the horizontal plane, the article supporting members of the conveyor units being arranged between the vertical plane of the first guide member and the first guiding means and the vertical plane of the carrier means when the conveyor units are moving along said curving main track section.
The first and the second main track sections will normally be horizontally oriented. The endless carrier means is normally, and in most cases preferably, a chain, but also other means, such as, e.g., a toothed belt or an endless series of connected carriages, which are capable of carrying the conveyor units in the manner disclosed herein are contemplated.
The main axis of each conveyor unit is preferably horizontal or substantially horizontal. In most cases, it will also be preferred that the main axis of each conveyor is substantially perpendicular to the transport direction.
The pivotal connection of each of the conveyor units with its article-supporting member, e.g. a cross-belt unit, extending away from the vertical plane of the carrier means permits a design where sections of the track can be mounted in an open space or on a wall as desired. Curvature of the track in a vertical direction, e.g. a vertical loop connecting two substantially straight track sections and reverting the direction of the track, can be compensated for by the conveyor units pivoting around their main axis, the maintaining or substantially maintaining the article-supporting member, e.g. a cross-belt unit, in its position relative to the horizontal plane, normally a position where the article-supporting surface of the member is horizontal, being achieved through the engagement of the guide member with the first guiding means. In most embodiments, the first guiding means will extend substantially parallel to at least a part of the main track. The first guiding means may in itself be a track with which the first guide member of each carrier unit engages, or it may comprise, e.g., protrusions such as pins or bars, which move along a path which normally extends substantially parallel to at least a part of the main track and which engage with the first guide member of each conveyor unit.
Torque-absorbing means may preferably be arranged in substantially the same vertical plane as the carrier means. This means that the torque-absorbing means will normally not extend further from the main track, normally in the direction opposite to the article-supporting member, than four times the breadth of the main track, preferably not further than three times and more preferred not further than twice the breadth of the main track. In an illustrative, but presently not preferred embodiment, the torque-absorbing means could be a relatively heavy counterweight placed on the opposite side of the carrier means relative to the article-supporting member of the conveyor unit; the counterweight could be adjustable to compensate for variations of the loading on the article-supporting member, the compensation being performed manually or preferably automatically, e.g. in response to a sensor detecting the angle of the article-supporting member of the conveyor unit relative to the horizontal plane and producing an output signal indicating the detected angle.
In practice, the torque absorbing means preferably constitutes an integrated part of the carrier means, such as, for each conveyor unit, at least one wheel or low friction slide part/slide member/slide shoe connected to or forming part of the carrier means and engaging with a track part, preferably a part of the main track, and co-operating with another engaging member, e.g. another wheel on a common axle, in such a manner that the torque is absorbed while permitting free movement of the total arrangement in the transport direction. An embodiment of such a torque-absorbing means is shown in the figures. It will be understood that in principle, to be comparable to the counterweight example above, such a torque-absorbing means consists of the combination of e.g. the wheel pair on the common axle and the track parts with which each wheel engages, and such a combination and similar combinations are covered by the term xe2x80x9ctorque absorbing meansxe2x80x9d herein.
The conveyor according to the invention may further comprise a second guiding means that extends substantially parallel to at least a substantial part of the main track, each conveyor unit comprises a second guide member adapted to co-operate with said second guiding means when the conveyor unit moves along at least a substantial part of straight sections of said main track, the second guiding means and the second guide members when co-operating are adapted to counteract or prevent the article-supporting member from tilting from its position relative to the horizontal plane.
To reduce the risk of tilting or instability in the transition from a straight to a curved main track section or vice versa, the first and second guide members of each conveyor unit and the first and second guiding means are preferably adapted so that the first guide member co-operates with the first guiding means when the conveyor unit enters the curving main track section and before the second guide member disengages with the second guiding means and so that the second guide member co-operates with the second guiding means when the conveyor unit leaves the curving main track section and before the first guide member disengages with the first guiding means. It will be understood that in some embodiments, the function of the second guide member can be performed by the first guide member so that both the first and the second guide members are constituted by one and the same guide member.
The second guide member and the second guiding means are preferably arranged in substantially the same vertical plane as the carrier means or in a vertical plane closely adjacent to said plane.
To further improve the stability when the first guide member travels through such parts of the first guiding means whose path may geometrically allow movement of the first guide member along their tangent (which means that in this situation there is no well-defined position of the first guide member in the first guiding member), the first guide member of at least one conveyor unit and preferably of all the conveyor units may comprise two wheels arranged in substantially the same vertical plane with a spacing between them and arranged pivotally on a bar which is arranged on the conveyor unit such that said bar is allowed to pivot about a third axis that extends substantially midway between and substantially parallel to the axes about which said two wheels are allowed to pivot, said third axis being substantially parallel to the first axis of the conveyor unit, the first, second and third axes of the conveyor unit being arranged with a spacing between each axis, and the first guiding means comprising a track protruding from a vertical plane and comprising two parallel surfaces with which said two wheels engage with said track in between said two wheels when the first guide member engages with the first guiding means. At least one of said two wheels of the first guide member is advantageously resiliently biased against said track of the first guiding means when the first guide member engages with the first guiding means.
It will be understood that the above stability-increasing embodiment may be generalized to other designs which further increase the stability of the movement of the conveyor units by increasing the degree of definition with which the respective guide members engage with their guiding means.
In order to further increase the stability of the conveyor, it may comprise a third guiding means arranged in substantially in the same vertical plane as the first guiding means, each conveyor unit comprises a third guide member adapted to co-operate with said third guiding means, the second and third guiding means being adapted so that the third guide member co-operates with the third guiding means when the conveyor unit enters the curving main track section and before the second guide member disengages with the second guiding means and so that the second guide member co-operates with the second guiding means when the conveyor unit leaves the curving main track section and before the third guide member disengages with the third guiding means.
Furthermore, the conveyor may comprise a fourth guiding means arranged in substantially in the same vertical plane as the first guiding means, each conveyor unit comprises a fourth guide member adapted to co-operate with said fourth guiding means, the first, third and fourth guiding members of each conveyor unit forming an obtuse-angled triangle in a vertical plane.
In one embodiment according to the invention, the conveyor comprises first, second and third guide members of each conveyor unit and first, second and third guiding means being adapted so that the first guide member co-operates with the first guiding means when the conveyor unit enters the curving main track section and before the second guide member disengages with the second guiding means, so that the third guide member co-operates with the third guiding means before the first guide member disengages with the first guiding means when the conveyor unit passes a given position along the curving main track section, and so that the second guide member co-operates with the second guiding means when the conveyor unit leaves the curving main track section and before the third guide member disengages with the third guiding means.
In a simple embodiment of the conveyor according to the invention, the first guide member comprises a wheel arranged on the conveyor unit such that said wheel is allowed to pivot about a second axis that forms the center axis of the wheel, said second axis being substantially parallel to the first axis of the conveyor unit and the first and second axes of the conveyor unit being arranged with a spacing between them, the first guiding means comprising a track that extends in the full length of the main track and in which track said wheel is moving, and the path of the track relatively to the main track is adapted to counteract or prevent the article-supporting member from tilting from its position relative to the horizontal plane.
Another embodiment based on the above basic design and having an increased stability compared thereto further comprises a second guiding means, at least one conveyor unit and preferably all conveyor units further comprising a second guide member adapted for engaging with said second guiding means, said second guide member comprising a wheel arranged on the conveyor unit such that said wheel is allowed to pivot about a third axis that forms the center axis of the wheel, said third axis being substantially parallel to the first axis of the conveyor unit and the first, second and third axes of the conveyor unit being arranged with a spacing in between each axis, the second guiding means extending substantially parallel to the main track over at least a substantial part of the curving main track section and comprising a track in which said wheel of the second guide member is moving, the path of the track of the second guide means relatively to the main track being adapted to counteract or prevent the article-supporting member from tilting from its position relative to the horizontal plane.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 shows an overview of a conveyor system according to the invention;
FIG. 2 shows a cross-section of a profile forming the main track;
FIG. 3 shows a cross-section of a first embodiment of the main track equipped for operation;
FIG. 4 shows a cross-section of a second embodiment of the main track equipped for operation;
FIG. 5 shows a cross-section of a third embodiment of the main track equipped for operation;
FIG. 6 is a perspective view of a first embodiment of a drive chain as seen partly from below;
FIG. 7 is a perspective view of a first embodiment of a drive chain as seen partly from above;
FIG. 8 is a perspective view of a second embodiment of a drive chain as seen partly from below;
FIG. 9 is a perspective view of a second embodiment of a drive chain as seen partly from above;
FIG. 10 is a side view of a first embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 11 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 10;
FIG. 12 is a side view of a conveyor unit according to the embodiment of FIG. 10;
FIG. 13 is a side view of a second embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 14 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 13;
FIG. 15 is a side view of a third embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 16 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 15;
FIG. 17 is a side view of a fourth embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 18 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 17;
FIG. 19 is a side view of a fifth embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 20 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 19;
FIG. 21 is a side view of a sixth embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 22 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 21;
FIG. 23 is a side view of a seventh embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 24 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 23;
FIG. 25 is a side view of an eighth embodiment of arrangements for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 26 is a cross-sectional view of a conveyor unit according to the embodiment of FIG. 25;
FIG. 27 is a side view of a preferred embodiment of an arrangement for preventing the conveyor units from tilting when passing a vertical half-turn of the main track;
FIG. 28 is a first perspective view of the arrangement of FIG. 27;
FIG. 29 is a second perspective view of the arrangement of FIGS. 27 and 28;
FIG. 30 is a perspective view of a first conveyor unit;
FIG. 31 is a perspective view of a second conveyor unit; and
FIG. 32 is a perspective view of a conveyor unit with the cross-belt part hinged to a frame part of the conveyor unit.